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E39 (1997 - 2003) The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

I've been waiting for over three months to have my head replaced on my 528i as referenced here in my prior post (http://www.bimmerfest.com/forums/sho...715&highlight=). The mechanic emails me today and says that the head is completely assembled and the car has been running fine for a week, no overheating whatsoever...(FINALLY, YIPPEEE!!!) However there is another issue he says that he wasn't aware of. Rough idling and misfiring in the second cylinder. He says that the constant overheating has destroyed the piston rings there. Now....for the interesting part........my options would be for him to go back in and replace the rings (he says this is a 50/50 shot because there could be more problems than just that), replace the whole "bottom" (short block?) of the engine, or get my car as is. Choices, choices, choices. I have a few questions that I need help with here great Bimmerfest folks:

1. Is he correct with what he's saying about replacing the rings? He stated it wouldn't be cost effective and I'm thinking this is something he should have checked with the whole head replacement. Am I right or not?

2. What could I expect to pay to have the "bottom" of the engine replaced? Does this option sound viable and also cost effective? I guess cost is in the eye of the beholder, so to speak, but I want to make sure this would be the best option for the situation.

3. What does a non working cylinder mean in terms of performance, driveability, long term damage, etc.??? He's telling me that he's driven cars without one or two cylinders properly working and once the car is running, there are no noticeable signs of a problem. I just figured when it comes to cars, if they put it in there, it was meant to work and that means this should be working, not just something I should just accept and drive on. Honestly speaking, I've had it since February and only driven it about a month's time. I'm itching to really break it in, and want it back ASAP, but not half way done.

I know this got lengthy, but I would appreciate any help and constructive opinions.

You need to see what the compression is in all of the cylinders.
If the rings are that bad there might have been score marks on the cylinder walls that he should have seen when the head was off.
I would hope that he would have cleaned the carbon off the top of the pistons and checked all of the cylinder walls when the head was pulled.
You really shouldn't be driving it with a cylinder misfiring.

Sorry to hear this,it will not be cost effective to repair your bottom end,I would find a replacement botton end and fit your reconditioned head,I wouldn't 're-ring' this engine after an overheat there are too many other issues than just rings (for example headstuds,pistons and and possibly bearings).
If your repair shop had a good knowledge of the motors I doubt if they would have gone ahead with just a cylinderhead repair
Change mechanics as well as your bottom end ,his comments about "dead " cylinders left me lost for words,its most likely this engine wouldn't run for long in this condition.
Good luck.

Thanks for the replies. I didn't think that would be a great idea. You want to know what's really crazy? This guy has had my car for the head replacement since Sept 10 and just sent this email now. That means he's had my car for 3 month 2 days. My transmission went on my 01 Tahoe in the first week of November. Talked to a friend of my dad who has a transmission shop and he rebuilt the tranny in exactly one week!!!! Dropped it off on Sunday and picked it up the next Sunday. I personally don't know the time involved in each job, but I know the tranny rebuild was a major job and my bimmer should have been back. The only reason I wasn't raising hell about getting my car back was because I had to use the money to get the tranny fixed. That was then and this is now. Anyone know what this part (bottom end of engine) and job might cost me? I live in middle GA, but would be willing to travel to the Atlanta area to get it done. I guess now I'll start the search for the engine bottom see what I can come up with. Thanks guys......and girls if there were any.....lol

You can test the efficiency of the rings by doing a simple wet / dry compression test.

Remove all the spark plugs and the fuel pump fuse, relieve the fuel system pressure and do a dry compression test in all the cylinders. Record the numbers. They should all be roughly the same, within 10 % of each other. If one is significantly different from the others, then that cylinder is leaking.

To determine if the RINGS are leaking:

Go back and do the compression test again, but this time put 2-3cc of engine oil in the spark plug hole first. Record the numbers. If there are bad rings, the pressure will be significantly higher for the wet test since the oil seals the leak past the rings temporarily.

Let us know what you find.

I'd say that if the rings were bad enough to be causing a misfire, it would have been visible as scoring on the cylinder walls, and he should have notified you of this before continuing after the cylinder head was removed. Either he's wrong about the rings and something else is causing the misfire, or he missed the diagnosis, plain and simple.

Thanks for the replies and the help. What I need help with now is where to find a short block for sale. A google search brings up many sites that don't have them or want you to send emails or calls. I'm trying to get a good idea of what one will cost, but I need somewhere reliable to look first. Any suggestions as far as used or rebuilt short blocks?

You need to see what the compression is in all of the cylinders.
If the rings are that bad there might have been score marks on the cylinder walls that he should have seen when the head was off.
I would hope that he would have cleaned the carbon off the top of the pistons and checked all of the cylinder walls when the head was pulled.
You really shouldn't be driving it with a cylinder misfiring.

+1 on what JimLev said as well as most everything else stated above.

I don't know how long you can wait but I will have a good running 528i motor available as soon as I can get a chance to pull it. I'm doing a swap to a built up M54 engine and the car is currently off the road for the winter. I would still get a second opinion on the diagnosis before going further.

I'll shoot you the pm regarding price and everything along with it. I know pictures say a thousand words, so here are a few. Hope I did this right. Anyways, look at the second cylinder and you can see how there is no carbon build up like the other cylinders. It was being "steam cleaned" by dumped coolant, right? I was told we need to check the plugs, coils, spark plug boots, etc. etc. But I think from these pictures we can see, this would cause this misfiring issue based on a problem in that cylinder. Am I correct? Thanks. Sorry about starting this post without the pics since he sent me these pics early on. Just thought about it tonight when looking at the replies again.

Finally got my car back........this turned out to be an ugly situation. Dropped my car off on Sept 10, 2011 and got my car back on March 1, 2012. Here's the rundown: head fixed and no overheating, cylinder #2 was misfiring, he stated pressure there was only about 60 and should be around 160. He replaced the short block with one he purchased from someone, possibly one of the BMW forum type sites, and guess what? Still misfiring in cylinder #2!!!! Now there's no smoke from tailpipe and the pressure is about 120-125. The car has a rough idle and you can feel the misfiring as you try to accelerate. I had to take my car this time, couldn't leave it with him any longer. There are some other issues with the car as well.....odometer and speedometer don't work, passenger side fog light fell out after I drove from the shop and parked (10 to 15 miles away), oil spots on the interior, bumper was loose.......of course this is all bad , but minor when compared to the engine running horribly. I'm at my wit's end about this and want to bring my bimmer up to its full potential. I'm planning on getting an engine this summer. We'll see where this goes.....fixed my fog light and bumper, cleaned the oil spots, and will need some help with odometer and speedometer.......

Not ready to throw in the towel yet...... paid almost $8000 a year ago and have put a little more than $2000 into it. BTW I didn't pay for this replacement block, he had to eat the cost of it, only paid for replacement head. Haven't had the true satisfaction of owning and driving a BMW yet. Not done yet.....thanks for the advice though.